Gas-filled tube



Dec. 2,8, 1937. L K SWART 2,103,439

GAS-FILLED TUBE Filed April 9, 1935 2 Sheets-Sheet l E .HEMI/ated or 5m mctivaced 1 R @n/ md w ce Conduct-L' E f l swgmng 71701-1; Circuit HNVENTOR BY W Q ATTORNEY l nel electrode S vand one oi* the internal electrodes ci the tube T.

It tne source B is one of continuous direct current, such as a storage battery, and poled so that the anode A is rendered positive with respect to the cathode K, the potential of the source being greater than the sustaining voltage but less than the breakdown voltage of the tube, the application of a sulicient potential between the external electrode Sand theinternal electrode K will initiate ionization within the tube, as already en plained. Now. if the potential applied between the electrodes S and K is such that the electrode S is rendered suciently positive withrespect to the cathode K, the initiation of ionization within the tube will 'take place particularly because oi the potential impressed between these electrodes S and K. After ionization taires place current will ccntinuously ow from the battery B through the load O and over the work circuit which extends to the electrodes A and K, and this woris circuit will be continuously energized irrespective of the potential .applied to the actuating circuit. In other words. the work circuit will be continuously operated even when the potentiel applied between the actuating electrode S and the cathode Ei is removed. The work circuit. can be returned to its normal and unoperated condition by cle-ionizing the ,gas within the tube, and this may be accomplished, ior instance, by opening the work circuit, as for example, by means of a switch (not shown).

It, however. the potential applied between the external electrode S and the cathode K is such that the enter-nal electrode is rendered sumciently negative with respect to the cathode K, this potential of the actuating circuit will be edectively in series with the potentiel oi the source B and both potentials will be additive and may create a sumcient potential between the electrode S and the anode Aso as to ionize the gas within the tube T. In other words, `the actuating potential may be such as to bring about a voltage ecct between the electrodes S and A sucient to ionize the eas within the tube. When this. occurs the worlr` circuit will again be operated and current will continuously ow from the source E through the load 0 and over the work circuit. Again the work circuit may be returned to its normal condition and the gas within v'the tube cle-ionized by opening the work circuit or by other means, and ii the work circuit is not returned to its normal condition. current will continuously flow from the source B irrespective oi the presence or absence thereafter oi potential betweenthe electrodehs S and K. I

It the source B were one which produced interrupted direct current the potentialoi which was greater than the sustaining voltage and less than the breakdown voltage of the tube T, ionization within the tube T `may be initiated by applying a sufdcient potential between the-electrodes S and K, and a pulsating current will therefore ow through the load O and over the work circuit. This pulsating current will cease just as soon es the potential applied to'the actuating circuit is removed or is rendered ineiective. Similarly, if the source B is one oi alternating current, alternating current or rectified current depending upon tube design will ow through the work circuit only as long as suicient potentiel is applied to the actuating circuit. In other words, the tube will automatically reset itself so that the gas therein will become de-icnized immediately after the applied potential is removed arcanes from the actuating circuit in those cases in which the source B is a pulsating potential or an elter-A nating potential. If, however. the source l5 is a continuous direct potential, any of the circuits shown in Y Patent No. 1,977,256, issued October it, 193e, may be used ior the purpose oi resetting the circuit to normal. l l

'mie tube T encloses vtwo electrodes both ci which are solid electrodes which are spaced from each other by a predetermined distance. This/10 tube may, of course. include many more than two electrodes if desired, and any two ci the electrodes may be used for connection to some form of wort: circuit. In fact. each pair oi electrodes may icrin individual circuits all simultaneously controlled by a single actuating circuit. v.also each work circuit may include a coon electrcdewithin the tube and one or the other electrodes. all of the circuits being simultaneously controlled by s single actuating circuit.

- It will be further noted that the electrodes A and K of the tube T are slriow'l'i as dat plates which iace each other.` These electrodes may be circularor rectangular in shane, or of any .other shane; and they need not be dat, they may be curvilinear, that is, either convex or concave, to any desired degree. Ii the electrodes are of equalereaas shown in Fig. 1 ci the drawings, the worls circuit may be completely reu versed so that the source B may apply, for instance, uegative potential to the electrode A and a positive potential to the electrode K. Under such conditions with alternating potentials supplied at B a substantially equal current wlli iow in either direction through the worl; c'ircuit aiter ionization is initiated by supplying a sumcient potential to the actuating circuit. These electrodes A and K need not be equal nat plates, i

however, but may be ci any conguraticn or one or both may be pointed if so desired. If a pointed electrode is enclosed within the tube it is preierable, however, that the source B be so poied as to render the pointed electrode positive with re= spect to the other electrode. A somewhat greater current will ow through the work circuit under such conditions than when the work circuit is reversed so as to reverse the polarity of the source B applied between the pointed electrode and the at electrode.

Although the external electrode S is shown in the form of a metallic band the plane of which is perpendicular to and bisects the gap formed by the electrodes A and K of the tube T, such an arrangement is by no means essential. The electrode S need not surround the envelope of the tube 'and it need not lie in a plane which is perpendicular to the direction of the gap between electrodes A and K; the electrode S may form any desired angle with respect to the direction `of the gap formed .by electrodes A and K.

The electrodes A and K, and any other electrodes enclosed within the envelope oi the tube, may, if desired, be coated with an activating material of any type well known in the art. This is not an essential requirement for the opera tion of any of the arrangements employed in this invention, but if the internal electrodes are so coated the eiiiciency and stability of operation of the tube will be increased and. moreover, a lower potential will be required, not alone for initiating ionization within the tube, but a lower potential will also sumce to continuously maintain ionization within the tube. i

Fig. 2 shows a tube T which resembles a type 75 aided by of cold cathode discharge tube familiar to those skilled in this art. This tube T includes within its envelope a pointed anode A and two cathodes which are spaced from each other but which are, in this invention, connected to each other so as to form a single cathode K. The commercial type of tube T; however, is improved in accordance with this invention by the presence of an external electrode S which is a conducting surface placed about the envelope ofl the tube T, as shown.

The work circuit of the tube T includes not alone the anode A and the cathode K of the tube T. butalso a source B and the winding of a relay R which are in series with each other. The

external electrode S is connected to the cathode K by means of a resistance Z and a source C which is used for biasing the external electrode S with respect to the cathode K. A source of actuating voltage P in the form of an alternating current generator is connected across the impedance Z. i

The source C, although it biases the external electrode S with respect to the cathode K, is insufficient by itseii to initiate ionization ci* the gos within 'the tube T. It is necessary that the actuating; voltage l? be applied through the im patience between the external electrode S and the cathode in addition to the eiect ci the source C to initiate ionization or the ses within the tube. It seems hardly necessary to state that aiterioniaation is initiated current flows the source B through the work circuit and operates the reiay or other load it. 'ii the source is one ci" continuous direct current reiay or load c't wiii be continuously operated until the work circuit is opened. or if a resetting employed. until the gas within the tube 'I is otherwise restored to a cle-ionized stat-e. 'the source is pulsating potentiai or au alterz ng the worlr circuit wili be stored to its initial condition and the reiay or load Et wil become unoperated upon removal ci the applied voltage P.

The irripeclonce Z is employed for the purpose ci removing any charge upon the conducting sur face .Si after the actuating voltage F has disconnected from the circuit. .any charge ou externai electrode S will leali baci. to the cathode (or ground) through Z and tins leaiz rriii occur whether or not a biasing source of poteriEl tial C is employed.

it will be understood that 'the actuating voltase need not be an alternating potential. It may be a sufficient direct potential, or any other form ci potential. It is 'the combined effect of the actuating potentiai P and the biasing cotentiei C, where the two are sumcleritly largefthat no duces ionization oi the gas within the tube T. however, the combined effect of the sources C is such as to render the external electrode positive with respect to the cathode and the source B ls such as to' render the anode A positive with respect to the cathode K, ionication will take place by virtue of the initial pc tential applied between the electrodes S and .if the combined eiect of the sources l? and C is such as to render the eaternai electrode S negative with respect to the cathode It., this corro blned eiect will produce between the external electrode S and the anode .A a voltage which is the source B. This potential applied between the electrodes S and A may be suicient to ionize the gas within the tube T and bring about the operation of the work circuit.

It will be understood that if the source B produces a pulsating potential or analternating potential of such a character that the interval between applications of voltage between the electrodes A and K is less than the time requireclto de-ionize the gas within the tube T, the gas within the tube T will remain continuously ionizedlV I irrespective of the application of any potential to the external electrode S. The work circuit may then be returned to normal byremoving or otherwise suppressing the actuating voltage P, as already described hereinabove.

It will be further understood that the source C is not indispensable ir the practice of this invention. It may be entirely eliminated inwhich case there would be no bias between the external electrode S and the cathode K. Under such conditlons the actuating voltage would itself bring about the initiation of ionization by applying potential to-the external electrode S and one of the other internal electrodes of the tube. Y

It will be still further understood that in the tube T', as in each ci' the other tubes to be hereinafter described, the anode A and the cathode K, may both be solid, metallic elements of equai area in which case the work circuit be re-s versed without in any way appreciably affecting its operation.

Fig. 3 is modification of the arrangement shown in Fie. 2 in which the source C biases the anode with respect to the external electrode the biasing potential i? being appiied'through the impedance Z. This arrangement operates in the manner already described with respect to Fie. 2.

'i shows tube T the Work circuit of which is connected between the anode A and. the cath ode E, as in 2. "ie tube T of this arrangement, however, two external conducting electrodes Si and S2, both of which are for convenwracped about the envelope of the tube and arenormally insulated from each other. or" these external eiectrories is connected to the anode A or the cathode K of the tube T, or to the Werl: circuit which is connected to these electrodes. e

The leak impedance Z is connected between the external eiectrorles El! and .'32 through the biasing buttery C, but it rliil be app .rent neither the battery @D rior the lingoedance Z; is essential to the operation ci the system. As in Figs. 2 and 3 the actuating voltage P may take the form of a gencrater of alternating current which produces e. potentiai across the terminals of the impedance 'Z. in this arrangement the biasing potential C is insuilcient alone to initiate gaseous ionization within the tube T, butthe additionai voltage de rived from. actuating source P and applied between the eiectrodes Si and S2 is sumcleutly large to initiate ionization. Thus c. discharge occurs between the electrodes A and K, .and the work circuit 'then supplied with current from `the source The tube T and its conductive external elec= trories Si Se are admirably adapted for signaling circuits in which one of the circuits or" the system may be oonductlvely dissociated from another of the circuits oi the system. In a telegraph system, for instance, the electrodes Si and Si: may be connected to one of the circuits, and the anode A and cathode K may be connected to another of the circuits. No current will flow through the circuit of the anode and cathode until a suiicien't voltage, properly poled, becomes applied to the electrodes Si and S2. The circuit or Fig. 4 is especially useful because there need Neither 1. The combination of a gas-lled tube enclosing two solid unheated substantially equal metallic electrodes spaced from each other, an electrode mounted external oi' the envelope of the tube, and means including a second electrode mounted external to the envelope of the tube for applying a potential between the iirst-mentioned external electrode and the second-mentioned external electrode so as to produce gaseous ionization between the internal electrodes of the tube, the circuit of the internal electrodes being uncontrolled by the external electrodes after gaseous ionization has been initiated.

2. The combination of a gas-lied tube having two solid unheated substantially equal metallic electrodes spaced from each other and an external electrode, means including a second external electrode for applying a potential between the two external electrodes for initiating ionization of the gas within the tube between its internal electrodes, and means connected to the internal electrodes for continuously maintaining the gaseous ionization within the tube independently of the presence or absence of potential between the external electrodes.

. 3. The combination of a. gas-filled tube enclosing two solid unheated substantially equal metallic electrodes spaced from each other and having two external electrodes, a source of potential connected between the internal electrodes the magnitude of which is insuiilcient to break down the gap between the internal electrodes but is greater than that required to maintain gaseous ionization within the tube after it is started,

means for applying a source of potential between the external electrodes for initiating gaseous ionization within the tube, and a load connected to the internal electrodes of the tube which becomes continuously operated after gaseous ionization is initiated and is thereafterV independent oi the magnitude or polarity of the potential applied to said external electrodes.

4. The combination of a gas-lled tube having two internal electrodes and two external electrodes, the internal electrodes being hard metallic elements, a source of potential, a load connected in series with the source of potential between the internal electrodes of the tube, a

` leak resistor connected between the external electrodes, and means for applying a potential across the leak resistor so asto initiate gaseous ionization within the tube and for continuously operating the load thereafter independently of the removal of the voltage applied across the leak resistor.

5. The combination of a gas-filled tube having two hard metallic internal electrodes and two external metallic electrodes, means for biasing one of the external electrodes with respect to the other of the external electrodes, means for applying a potential between the external electrodes so as to initiate gaseous ionization within the tube, and means connected to the internal electrodes of the tube for continuously maintaining gaseous ionization within the tube uninuenced by transient 'variations in the magnitude, polarity or phase o! the potential thereafter remaining onthereaiterapplied to said external electrodes.

6. The combination o! a gas-nlled tube having two hard metallic internal electrodes and two external electrodes which are spaced and insulated from each otherQa work circuit connected between the internal electrodes of the tube, and means forapplying potential between the external electrodes for initiating gaseous ionization within the tube and for continuously operating the work circuit uniniiuenced by transient variations in the magnitude, polarity or phase of the potential thereafter remaining or thereafter applied to said external electrodes.

7. The combination of a gas-lilled tube havingA two `hard metallic internal electrodes and two external electrodes which are spaced and insulated from each other, a work circuit connected between the internal electrodes of the tube which includes a source of potential the magnitude of which is less than the voltage required to break down the gas between the internal electrodes of the tube and greater than that required to sustain ionization between said internal electrodes of the tube after ionization has started,

internal electrodes and two external electrodes a source of potential the magnitude oi which is less than the potential required to initiate ionization of the gas within the tube, a load interconnected between the source of potential and two of the internal electrodes of the tube, and means for applying a potential between the external electrodes for initiating gaseous ionization .within the tube and for operating the load uniniiuenced by transient variations in the magnitude, polarity or phase of the potential thereafter remaining or thereafter applied to said external electrodes.

9. The combination oi a gas-lilled tube enclosing a plurality of solid metallic electrodes 4spaced from each other, a plurality of electrodes mountedsexternal of the envelope of the tube which are not connected to the internal electrodes, and means for applying a potential to the external electrodes to produce gaseous ionization between the internal electrodes oi the tube.

10. The combination of a gas-lled tube enclosing a plurality of unheated metallic electrodes spaced from each other, a plurality of external electrodes for the tube which are not connected to the internal electrodes, and means for applying a potential to the external electrodes for initiating ionization o1 the gas within the tube between its internal electrodes.

11. The combination of a gas-filled tube enclosing a plurality of solid unheated metallic electrodes spaced from each other and having a plurality of external electrodes not connected to the internal electrodes, a source of potential connected to the internal electrodes the magnitude of which is insuillcientto break down the gap between the internal electrodes but is greater than that required to maintaingaseous ionization within the tube after it is started,- and means for applying a potential to the external electrodes for initiating gaseous ionization within the tube.

l Lamm: KAssoN swAaT. 

